Guiding light system for trailer tow car hook-up

ABSTRACT

This apparatus embodies equipment to produce in front of the driver of a tow car two signal devices in the form of lamps which show the driver of the car whether or not it is backing directly toward the hook-up position to attach a trailer coupling when it is close to this position and when it reaches hook-up position. The signal devices are right-hand and left-hand lamps, mounted on the dash or the instrument panel of the car. At the rear end of the car two spring contactors are mounted on the car side by side. A cable passes between the contactors and is wound on a spring take-up reel that is spaced in front of the spring contactors on the car. The cable is an electricity conductor and has means, insulated from the cable at its free end to attach it to the trailer coupling. The lamps each have one terminal connected to the ungrounded side of the car battery and the other terminal connected to one of the spring contactors so that so long as the cable engages both contactors there is a circuit completed from the battery through each lamp then through its conductor to the spring contactor, then through the cable to ground and the grounded side of the battery. If the cable pushes either contactor away from the other one then the lamp connected to the other one has its circuit broken, and shows dark to the driver. The cable has an insulation, covering it adjacent to its free end to darken both lamps when the car is in close proximity to hook-up position.

United States Patent 1 Green [54] GUIDING LIGHT SYSTEM FOR TRAILER TOWCAR HOOK-UP [76] Inventor: Laurence Green, P.O. Box 1127,

Twin Falls, Idaho 22 Filed: Sept. 20, 1971 21 Appl. No.: 182,017

UNITED STATES PATENTS 2/1956 Thompson 12/1968 .....340/52 R Fenner..340/52 R Primary Examiner-Thomas B. Habecker Assistant ExaminerGlen R.Swann, III AttorneyWells, St. John & Roberts [57] ABSTRACT Thisapparatus embodies equipment to produce in front of the driver of a towcar two signal devices in 51 May 1,1973

the form of lamps which show the driver of the car whether or not it isbacking directly toward the hookup position to attach a trailer couplingwhen it is close to this position and when it reaches hook-up position.The signal devices are right-hand and left-hand lamps, mounted on thedash or the instrument panel of the car. At the rear end of the car twospring contactors are mounted on the car side by side. A cable passesbetween the contactors and is wound on a spring takeup reel that isspaced in front of the spring contactors on the car. The cable is anelectricity conductor and has means, insulated from the cable at itsfree end to attach it to the trailer coupling. The lamps each have oneterminal connected to the ungrounded side of the car battery and theother terminal connected to one of the spring contactors so that so longas the cable engages both contactors there is a circuit completed fromthe battery through each lamp then through its conductor to the springcontactor, then through the cable to ground and the grounded side of thebattery. If the cable pushes either contactor away from the other onethen the lamp connected to the other one has its circuit broken, andshows dark to the driver. The cable has an insulation, covering itadjacent to its free end to darken both lamps when the car is in closeproximity to hook-up position.

4 Claims, 5 Drawing Figures Patented May 1, 1973 2 Sheets-Sheet GUIDINGLIGHT SYSTEM FOR TRAILER TOW CAR HOOK-UP BACKGROUND OF THE INVENTION Asearch of the prior patents in this field revealed the following priorU. S. Pat. Nos. for the guiding of a tow car into hook-up position infront of a trailer:

Thompson 2,736,885

Tamis et al. 2,797,406

Knapp 2,927,310

Sparks et al. 3,237,177

Fenner 3,418,628

The Thompson patent uses a cable which turns on an arm to cause aflexible shaft on the trailer to swing a rocker arm on the trailer toright or left. A switch on the first mentioned arm is actuated bybumping a stop on the tow car and lights a lamp on the trailer. In theTamis et al. patent the tow car carries a series of contact pairs whichcan be bumped by the tip of the tongue on the trailer to light variouslamps on the dash of the tow car and indicate whether the ball on thetow car is aligned with the socket on the trailer tongue. The Knapppatent uses two telescoping feelers to actuate indicators in the tow carthat indicate lack of alignment of the longitudinal center line of thetrailer with the tow car. The Sparks et al. patent shows a coupling barto .control a dash indicator of right or left deviation of the trailer.The Fenner patent has an upstanding post on the trailer tongue to carrya series of lamps. These lamps are lighted by the tow car ball hittingone of a series of flaps on the trailer tongue to operate a switch.

SUMMARY OF THE INVENTION The purpose of this invention is to providemeans to direct the driver of a tow car in backing it into hook-upposition of its coupling unit with respect to the coupling unit on thetrailer, wherein two signal devices in front of the driver are actuatedby making and breaking contact between a spring retracted cable that ismounted on the tow car to extend rearwardly along the center line of thetow car through the rear end of the car and to the coupling unit on thetrailer, and a pair of spring mounted electrical contactors arrangedside by side, on the rear end of the tow car so that the cable, whentaut between its mounting on the tow car and the coupling unit on thetrailer can contact both contactors, or either contactor depending uponwhether the tow car is backing correctly or veering to right or leftwith respect to the hook-up coupling on the trailer.

It is also a purpose of this invention to provide a cable, in theforegoing assembly with insulation thereon to engage the contactors andtemporarily change the signal of the signal device as an indication ofthe proximity of the tow car to hook-up position.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a somewhat schematic plan sectional view of a tow car and atrailer to which my invention is applied showing the relative positionsof the parts;

FIG. 2 is a wiring diagram illustrating the electrical connections inthe device;

FIG. 3 is a detailed view partly in section showing the relativepositions of the tow car-trailer couplings and the cable;

FIG. 4 is an enlarged sectional view on the line 44 of FIG. 3; and

FIG. Sis a sectional view on the line 5-5 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to thedrawings the tow car dash is indicated generally by the numeral 1. Aportion of the frame of. the car at 2 carries a reel 3 which is providedwith a spring 4 to wind up a cable 5 thereon. This cable is anelectrical conductor and is grounded through the reel 3 to the car. Thetow car has a coupling unit 6 for connection to a complementary couplingunit 8 on a trailer 7. The coupling units 6 and 8 are shown asconventional ball and socket members respectively. The cable 5 may bedrawn from the reel 3 rearwardly and carries a hook 9 to engage a post10 on the coupling unit 8. There may be several feet of cable betweenthe tow car unit 6 and the unit 8 on the trailer. By aligning the towcar center line with the cable. The tow car can be backed directly underthe socket on the trailer tongue.

The cable 5 extends from the reel 3 through a casing 11 of insulatingmaterial which is mounted on the back end of the tow car at 13. Insidethis casing there are two electrical contactors 12 and 14 side by side.These contactors are coiled springs of stainless steel and they arespaced apart slightly to engage the cable 5 as shown in FIG. 4. Thecable if moved to right or left pushes one contactor and moves away fromthe other to break contact with it. The casing 11 is mounted to the towcar by two bolts 16 and 17. The contactors 12 and 14 are carried onwiring terminals 18 and 19 which are mounted on the casing l 1.

The terminals 18 and 19 are attached to insulated conductors 20 and 21,which extend forward to another casing 22, mounted on the tow car dash Iin front of the driver. This casing has two apertures 23 and 24 thereinand inside the casing are two small lamps 25 and 26 which providesignals to indicate when the cable 5 is in engagement with only one ofthe contactors 12 or 14 or is engaged with both and completing acircuit. The conductors 20 and 21 extend to a manually operated switch27 which, when closed, completes connection of the conductors 20 and 21to one terminal of each of the lamps 25 and 26. Conductors 28 and 29connect the other lamp terminals to the battery 30 of the tow car. Thus,when the switch 27 is closed the engagement of the cable 5 with acontactor 12 or 14 completes an energizing circuit for the correspondingsignal 25 or 26.

The cable 5 has means thereon to effectively inform the driver of thetow car when the coupling units are getting close to each other. This isdone by applying a plurality of coverings of insulation to the cable afew inches from the free end of the cable. These coverings are shown inFIG. 1 at 31, 32 and 33. When one of the coverings gets between thecontactors l2 and 14 both signals 25 and 26 go dark. So these threewarnings alert the driver. Then the fastening means 9 on the end of thecable is a hook made of a plastic which is an insulator. When thecontactors 12 and 14 engage this hook the unit 6 on the tow car isdirectly under the coupling unit 8 on the trailer and both signal lampsare de-energized.

The operation of this device is as follows. The driver of the tow carbrings it close enough to the trailer, with its rear end toward thetrailer, that the cable 5 can be pulled out against the force of thespring 4 until the cable is fastened to the coupling unit 8 on thetrailer. The driver then backs the tow car under the guidance of the twosignal lamps so as to keep the cable 5 in contact with both contactors12 and 14. When the first insulation covering 31 on the cable passesbetween the contactors the driver knows that the coupling unit 6 is inclose proximity to the coupling unit 8 on the trailer. He proceedscautiously until the fastening means 34 is between the contactors 12 and14 sufficiently to again break the energizing circuit for both signaldevices 25 and 26. This indicates that the coupling units are in hook-upposition.

The invention upon which a patent is requested is defined in thefollowing claims.

I claim:

1. In a tow car having on its rear end a central coupling unitconnectable to a complementary coupling unit on the front of a trailervehicle, apparatus on the tow car operable to signal the tow car driverto guide his backing of the tow car to bring its coupling unit intoposition to hook up to the trailer coupling unit, said apparatuscomprising:

an electrically conductive cable operatively connected to a firstterminal of a source of electrical current and having one end mounted inthe tow car forwardly of and in alignment longitudinally of the car withthe tow car coupling unit; a pair of side-by-side electrical contactorswith means supporting and insulating them on the tow car in alignmentwith and between the tow car coupling unit and the mounted end of thecable;

said contactors being mounted to yieldingly oppose separation and beingeach engageable with the cable therebetween; 7

spring means in the mounting of the cable end to the tow car urging thecable forwardly between the contactors;

said cable having means at its free end attachable to the trailercoupling unit;

signal means mountable in the tow car connecting each contactor to theremaining terminal of the source of electrical current; and

surface insulation on the cable adjacent to its free end operable toinsulate the cable from the contactors when engaged by the contactors.

2. The invention defined in claim 1 wherein the means at the free end ofthe cable for attaching the cable to the trailer coupling unit comprisessurface insulation material operable to insulate it from the contactorswhen engaged by the contactors.

3. The invention defined in claim 1 wherein the contactors comprisecoiled springs side-by-side and a casing of insulation in which saidsprings are supported in upright positions, said casing having means tomount it on the tow car.

4. The invention defined in claim 1 wherein the signal means comprises apair of lamps, a casing in which said lamps are mounted, said casinghaving laterally spaced windows, one for each lamp; and

means to secure the casing on the tow car dash.

1. In a tow car having on its rear end a central coupling unitconnectable to a complementary coupling unit on the front of a trailervehicle, apparatus on the tow car operable to signal the tow car driverto guide his backing of the tow car to bring its coupling unit intoposition to hook up to the trailer coupling unit, said apparatuscomprising: an electrically conductive cable operatively connected to afirst terminal of a source of electrical current and having one endmounted in the tow car forwardly of and in alignment longitudinally ofthe car with the tow car coupling unit; a pair of side-by-sideelectrical contactors with means supporting and insulating them on thetow car in alignment with and between the tow car coupling unit and themounted end of the cable; said contactors being mounted to yieldinglyoppose separation and being each engageable with the cable therebetween;spring means in the mounting of the cable end to the tow car urging thecable forwardly between the contactors; said cable having means at itsfree end attachable to the trailer coupling unit; signal means mountablein the tow car connecting each contactor to the remaining terminal ofthe source of electrical current; and surface insulation on the cableadjacent to its free end operable to insulate the cable from thecontactors when engaged by the contactors.
 2. The invention defined inclaim 1 wherein the means at the free end of the cable for attaching thecable to the trailer coupling unit comprises surface insulation materialoperable to insulate it from the contactors when engaged by thecontactors.
 3. The invention defined in claim 1 wherein the contactorscomprise coiled springs side-by-side and a casing of insulation in whichsaid springs are supported in upright positions, said casing havingmeans to mount it on the tow car.
 4. The invention defined in claim 1wherein the signal means comprises a pair of lamps, a casing in whichsaid lamps are mounted, said casing having laterally spaced windows, onefor each lamp; and means to secure the casing on the tow car dash.